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How to Grade a Piece of Diamond

Author:liliang Time:2017-12-28 15:17:03

A piece of diamond is valued by its grade, which is called 4C. Namely color, clarity, carat and cut.

Diamond color:The diamond color can be divided into two big series, the normal colorless series includes, colorless, slight yellow, slight beige; while color series include, dark yellow, grey and pink etc. The color of colorless diamond is usually based on the color grading of GIA established by US gemstone institute, and it starts with D (transparent and colorless, that is, the first letter from Diamond) to Z(yellow).

D grade: perfectly colorless diamond, the best and rare color.

E grade: colorless diamond, slight color can be only detected by gemstone professor, the diamond with this color is also very rare one.

F grade: colorless diamond. Slight color can only be detected by gemstone professor, but this kind diamond color is also regarded as colorless, which is belonging to high quality diamond.

G-H grade: nearly colorless, there will be very slight color when compared with high quality diamond, but this kind diamond color still has very high value.

I-J grade: closed to colorless, this kind color of diamond can be detected slight color, but value is good.

K-M grade: dark color diamond, people are not suggested to have it.

N-Z grade: very dark color, not suitable to be used into jewellery.

Diamond clarity grade, each piece of diamond contains natural inclusion, just like natural birthmarks. The number size, shape and color of these inclusions determine the cleanliness and uniqueness of a diamond. The inclusions are hidden in diamonds and can be colored in different colors: white, black, colorless, even green or red. Most of the inclusions can not be identified by the naked eye, and they must be seen under 10 magnifying glasses. Cleanliness is a classification system for measuring inclusions and defects: FL/IF(perfect without blemish/ internal flawless) to I (Flawed). I level cleanliness represents an intrinsic substance that can be identified by the naked eye. According to this principle, the clarity of diamond can be graded from high to low as FI, IF, VVS1, VVS2, SI1, SI2, P1, P2, P3ect. Under P grade, the diamond will be used in industry not jewellery.

Diamond carat grade: the weight of diamond is measured by carat, 1 carat =0.2g=100 points. 0.75 points can be also called 75 points. The value of diamond is increased according to the weight of diamond, in terms of other conditions are closed.

The same weight of diamond may have sharp different value due to the different color, clarity and cut of diamond. The Carat weight of diamond over 50 point will have maintained value. Bigger carat diamond is, more valuable the diamond will be.

Diamond cutting grade: diamond cut grade refers to the technician cuts the angle of diamond flap surface, and complete all parts of the proportion of diamond cutting. According to the scientific formula, perfect cut diamonds should be entered within the diamond light, as reflected by different internal valve surface, and finally condensed in the diamond on top of the bloom or side flow away, lost glory. Therefore, the good diamond cutting will possess high value.